Draw buggy



April 18, 1961 E. w. NILSSON DRAW 'BUGGY 2 Sheets-Sheet 1 Filed May 20,1958 N QE INVENTOR EINAR W.

NILSSON WORNEY April 18, 1961 E. w. NILSSON 2,980,238

DRAW BUGGY Filed May 20, 1958 2 Sheets-Sheet 2 FIG. 6

FIG. 5

\ L Q N INVENTOR EINAR w. NlLSSON ATTO EY United States. PatentO2,980,238 DRAW BUGGY Einar W. Nilsson, YoungstowuyOhio, assiguor to TheMcKay Machine Company, Youngstown, Ohio, a corporation of Ohio Filed May20, 1958, Ser. No. 736,622 3 Claims, c1. 205-3 and carries grippingmeans for engaging andholding', the

reduced or pointed end portions of the metal sections which areinitially loaded to project through the dies. The carriage, or drawbuggy as it is commonly referred to in the art, is adapted to grip theprojecting ends of the metal sections and then is moved outwardly, alongthe frame or bench, by means of a hook mounted on the draw buggyengaging a link of a continuouslydriven chain, for example, therebydrawing the metal sections through the dies to reduce and/0r shape thesame. Such 1 mechanism may also include means for removing the drawnmetal sections or stockfrom the draw buggy, meansv for returning thedraw buggy to its starting position adjacent the die block,automatichandling equipment for loading the pre-pointed metal sectionsinto the die block and for removing and handling the drawn metalsections or stock from the fram as well as suitable "controlapparatus'for effecting generally autorn'aticvoperation of the drawingmechanism in the desired manner. The general arrangement of this type ofdrawing-mechanism is shown and described in the prior United StatesPatents to Kerr and Andrews, Jr., et al., Nos. 2,404,234 and.

2,331,953, respectively, which are representative of the prior practicein the art and are made of record "for those desiring a more detaileddescription of thelsame,

It is theprimary or ultimate object of the present in vention to providean improved draw buggy of-the kind. adapted to be employed'with theabove described type of,

drawing mechanism. Whenever alplurality of dies a're employed andthe'draw buggy'fno'u'nts a plurality of means for gripping thepre-pointedT ends of, metal sectionsi.e.-in multipleidrawingfloperationsit is, necessary that all of the'projecting reduced ends ofthernetals'ections be properly gripped prior to movement of the drawbuggy and the inability of prior'art apparatus'to satisfactorily meetthis condition has resulted in several seriousfproblems. Failure of thegripping means to properly engage and grip one or morefof thepre-p'ointedends of" the meta l sections or stock is a frequent'causeofdelay in drawing operations and an interrupted draw may causeundesirable marking of the stock, T heseproblems have prevented, to acertain extent, the realization of theef-x;

ficiencies and economies inherent in drawing'mechanisni limited theemployment thereof and. methods of this general type and have jsoniewhat It'is 311611161 object or the invention)mismviaeaarw different metalsections in affastiand efiicient C6 Patented Apr. 13, 1961 2a a buggywherein the means for gripping the reduced ends of the metal sections isactuated to firmly and positively grip the same prior to the movementofthe draw buggy to draw the metal sections through the dies. As will bemore fully apparent, the gripping means is actuated to grip the ends ofthe metal sections prior to the release of the hook carried on the drawbuggy which engages the; continuously driven chain. v i

A further object of the invention is to provide appara tus of thecharacter described wherein a separate driving means for actuating thegripping means is mounted directly on the draw buggy and operative whenenergized to positively move the gripping means into gripping engagementwith the ends of the metal sections prior to movement of the drawcarriage. In accordance with this object, the draw buggy mounts anfelectricgear motor operating through new and novel linkage means toclose the gripping means in relatively independent. fashion whereby eachof the metal sections is firmly gripped prior to drawing. 7 I f jAnother important object of the present invention is to provide improvedmeans for powering or energizing the separate driving means mounted onthe draw buggy when the same is adjacent the die block. The draw buggymounts a forwardly projectingconnector and the dieblock mounts a matingconnector-so that when the draw buggy is against the die block thedriving means is energized to actuate the gripping means, It will benoted that this arrangement is parti cularly advantageous since thedriving means is energized at exactly the right time and remainsenergizecl ,to insure'positive gripping of the projecting ends of themetal s'ectionsuntil the actual drawing operation commences'and the drawbuggy moves outwardly from the dieblo clc, l

A still further object of the invention is to provide im v provedgripping means for a draw, buggy. Such gripping means comprises aplurality of sets of inwardly-converg' inggripper bits and improvedlinkage means for moving the sets of bits in relatively independentfashion to grip the pre-pointed ends of the, metal sections. In thismanner'each 'ofthe ends of the strip sections is firinly grippedirrespective'of diiferences in'the sizes and shapes of the saidends. ,jI, a Yetanother object of the present invention is to provide grippingmeans'of the type indicated whichris char".- acterized by its almostcomplete lack. of sliding friction; Inrprevious' gripping means theamount of sliding 'fric-' tion in the gripping means at thetime theendsof the metal sections are beinggripped isconsiderableandlthis' slidingfriction "may prevent ,a good" gripping action,

Another object of the invention istoprovideigrippirig" means, which iseasily and readily 'rernovedtor freplacei mentland/orrepairs. In thismanner theidrawirigjmech anism. may beused ior forming or shapingseveraldiffer ent sized o'r shapedmetal sections at one, timegorfjthe,enre r pp "me n y egc a 'g ditf ct ii I I anisrn An ancillaryobject ofthe present, invention'is to pro; vide a draw bu'ggy and gripping me'anstherefor having the characteristics outlined above ,which is ofsimplified andeconomical construction but it is yet welladaptedtdthereby providing more versatile drawing in withstand continuousmill-type operations. Q, 7 The above, as well as other objects'and,advanta'g' the invention", will become-more readily apparent upforifconsideration of the followingpspeciiication andacc'om{ ,panying drawingwherein there are disclosed certainfil lustrat ed, embodimentsconstructed inlacco rdance with-the: I

with: aprotective cover "for a portion of the driving teachings of lthepresentfinvention;V i 511 dr w Figure l isz'aplan view* of anfimprovedfdraw; uggy,

teachings of the present invention;

Figure 2 is a side sectional view of the draw buggy taken along thesection line II-II of Figure 1;

Figure 3 is an enlarged fragmentary end sectional view taken along thesection line lII- III of Figure 1;

Figure 4 is a fragmentary plan view of the forward end of a draw buggydepicting the improved gripping means;

Figure 5 is an enlarged fragmentary plan view showing specifically aportion of the gripping means; and

Figure 6 is a side sectional view taken along the section line VIVI ofFigure 5.

Referring now to the drawing, and initially to Figures 13 thereof, thereference numeral 10 designates a generally rectangular unitary frameformed with bifurcated projections 11 adjacent each corner thereof thatare spanned by transversely extending axles 12 which in turn journalwheels 13 by means of bearings 14. The frame 10 is thus supported formovement by transversely spaced pairs of longitudinally separatedwheels. The frame 10 has a large rectangular recess 15 for mountingthereon a gripping means 16, a driving means 17 for actuating the grippingmeans and a rearwardly projecting hook 18, all of which will behereinafter more fully described. The draw buggy is adapted forlongitudinal movement on a frame or bench 19 having spaced tracks, notparticularly shown, for the wheels 13 and mounts a continuously drivenchain thereon, also not shown. The bench 19 extends longitudinally inthe direction of drawing from a die block, indicated schematically bythe reference numeral 20, mounting a plurality of dies. In the normaland intended operation of such drawing mechanism the metal sections arefirst loaded into the dies with the reduced ends thereof projectingforwardly of the face of the die block 20. Then the draw buggy isreturned to abutting relation with the die block and the driving meansis actuated to move the gripping means to positively engage theprotruding ends of the metal sections. After, and only after, the endsare properly gripped the hook 18 drops and engages a link of the drivenchain and the draw buggy is moved outwardly of the die block therebydrawing the metal sections. When the drawing is completed the metalsections are removed, the hook 18 is disengaged from the driven chainand the draw buggy is returned to a position adjacent the die'block 20for another drawing operation. It will be observed that the abovedescribed operation is well adapted for automatic and continuouscycling.

Considering now the gripping means. 16 shown in Figures 1 and 2 of thedrawing, the forward ends of the frame 10 terminate in hook-likeinturnedportions 22 which engage vertical channels 23 formed on theoppositeendsof a grip bit block 24 in the manner shown.

The'.grip bit block 24 is provided with three pairs of converging guidechannels 25 each adapted to slidably receive a grip bit 26 havingaserrated forward end portion 27. The arrangement is such that the pairsof grip bits .26 may be slidably moved within the guide channels25incooperating fashion to grip the ends or .terminates in a forwardcollar 36 the forward face of which is adapted to have bearing contactwith the rear face of the grip bit 26 associated therewith. The forwardcollars 36 and the rear faces or surfaces of the grip bits are notrigidly connected but are adapted to contact each other in the mannershown. Surrounding each of the plungers 34 on opposite sides of thecrosshead 35 are the coil springs 37 and 38 which extend between therear faces of the forward collars 36 and the crosshead 35 and betweenthe crosshead 35 and the collars 31, respectively, and are of such adiameter that they will not pass through the apertures within thecrosshead.

The above described gripping means is similar to that shown anddescribed in the aforementioned Kerr patent, No. 2,404,234, and it willbe observed that forward longitudinal movement of the crosshead 35 alongthe axes of the plungers 34 forces the plungers to move along theirlongitudinal axes through drive connections provided by the coil springs37 and consequently the grip bits 26 move into their operativepositions. Rearward longitudinal movement of the cross head causes thegripper bits to retract through drive connections comprisingthe coilsprings 38, collars 31 and connecting rods 29 In effect, each of thegrip bits 26 is independently and yieldably mounted since a plunger 34,collar 31, coil springs 37 and 38 and connecting rod 29 are provided foreach individual grip bit in order that the ends of metal sections areproperly gripped regardless of differences in the size and shapethereof.

Rigidly connected to the crosshead 35 adjacent the opposite ends thereofare the forward ends of a pair of identical and generally parallel driverods 40. Each of the drive rods 40 is accurately guided for longitudinalmovement by apertures 41 and 42 provided in the collar mounting portion32 and forward end portion of the frame, respectively, in the mannershown. The drive rods 40 extend a'lrnpst the entire length of the frame10 and are further guided for longitudinal movement intermediate theirends by. a pair of integral apertured bosses 43 projecting intotherecess 15 from the frame 10 and by a pair of elongated and shoulderedspacers 44 carried thereby. The rear end portion of each of the driverods 40 'is'slidably received within a tubular fitting 45 having asegment of a rack 46 on the upper face'of the forwardend-portion thereofand an enlarged longitudinally extending bore 47 adjacent its rearend ofgreater diameter than the diameter of the drive rod. The tubularfittings 45 are suitably guided for longitudinal movement'with respectto the frame 10 by properly formed portions thereof as is readilyapparent. Received within the bore 47 of each of the tubular fittings 45is an externally threaded tubular portion 49 of a projecting latch 50whose use will be hereinafter more fully explained. The threaded'tubularportion'49 of each of the latches 50 is held in rigid relation with"respect to the tubular metal sections protruding from the die block 20.Each of the grip bits has a vertical bore 28 in the upper exposed rearsurface thereof which is, adapted .to receive one downturned end of aU-shaped connecting rod29.,i The other end of the U-shaped connectingrod is. received within a vertical bore 30 of a collar 31 that isguidedfor sliding movement in a properly formed collar mounting portion 32 ofthe housing. It will be notedthat the collar mounting portion 32 isformedwithslo'ts 33 to provide clearance for'the connecting rods 29andit is preferred, although not shown, that some means. such as j proections extending from the collar. guided in' suitable ways, he providedfor retaining the collars in proper alignment with the connecting rods.Secured. tofthe forward end of each of the collars 31 is a forwardlypro.-

fitting 45' QSSOClZItEd'IflCICVi/lth by means of a lock nut 51. It willthus be seen that the rear ends of the drive rods are slidably receivedwithin the tubular assemblies including the fittings 45'and thelatchesflSO while thesefitting 45 associated therewith and disposed onopposite sides of. this shoulder in...encircling relation with the driverod and within the confines of the tubular bore are spaced coil springs'54 and 55. The shoulders 53 form, fin eif ect, abutments and it will benoted that ifthe, tubular fittingsfand latches'are moved to the leftfrom their retracted positions the drive rods will-also.

be moved to the left under the influence of the coil springs while whenthe tubular fittings and latches are moved to the right the drive rodsare also driven by the coil springs. This provides, in essence, aresilient or yieldable driving connection between the tubular fittingsand the crosshead 35 and latches 50 carried by the drive rods.Positioned forwardly of the tubular fittings 45 between these lastmentioned members and the spacers 44 in encircling relation with thedrive rods 40 are a pair of return coil springs 56 whose function it isto return the tubular'fittings and consequently the drive rods to theirretracted positions in a manner to be further explained. The drivingmeans for actuating the gripping means comprises an electric gear motor58 having a rearwardly extending drive shaft 59 mounted within therecess 15 of the frame directly behind the gripping.means.- Keyed to thedrive shaft 59 is a bevel gear 60 which mates with anormally disposedbevelgear 61- mounted intermediate the ends of a transversely extendingsplined and shouldered shaft 62 whose ends are journaled by bearings 63in cup shaped bearing carriers 64 rigidly received within the frame 10.Also mounted on the shouldered shaft. 62 adjacent the ends thereof andadapted for rotationv therewith are a pair. of wheel gears 65 havinggearteeth along a portion of their circumferences adapted to nieshwiththeracks 46011 the tubular fittings-45 as clearly shown in Figure 2 of thedrawing. It'will thus be seen that upon energization of the electricgear motor 58 the tubular fittings '45 and consequently the drive rods40 and the crosshead ,35 and latches 50 mounted on the drive rods willbe moved in a longitudinaldirection by virtueof the meshing racks 46 andwheel gears 65 .which are interconnected by the above described gearingwith the electric gear motor 58. The driving means is so constructed andemployed and the drive rods, tubular fittings and latches are so guidedthat the drive rods will be actuated in exact synchronism and anyrelative movement between these members is precluded.

One of the important aspects of the present invention is the meansemployed for energizing the gear motor 58 for actuating the grippingmeans and moving the latches. This means comprises a suitable electricalconnector 66 mounted on and projecting from the forward end of the frame10. The electrical connector 66 is connected by suitable conduits, notshown, with the gear motor and the forward face thereof is aligned withthe forward edge of the'grip bit block. A mating electrical connector,not specifically shown, is mounted-on thedie block 20 and thearrangement 'is suchthat-when" the draw buggy is moved into abuttingrelation with the die block an electrical circuit is completed due tothe engage ment of the two connectors and energizing potential is thussupplied to the gear motor 58 to actuate the same thereby causingmovement of thedrive rods and actuation of the gripping means. However,whenthe. draw '6 7 element 69 which spans the recess 15 adjacent therear ends of the latches 50. ,The hook and back-up ele-' ment aresuitably apertured to define a transverse bore,

70.which receives the transversely extending latch rod 71 and it will benoted that appreciable portions 'of the circumferential surface area ofthe latch rod adjacent the ends thereof and overlying the latches areexposed while the portions between the hook proper and the end portionsare completely exposed. Mounted on the latch rod on these last mentionedportions on opposite sides of the hook proper are a'pair of downwardlydepending cams 72 whose function it is to cooperate with cam members,not shown, mounted on the bench for raising the hook. The ends "of thelatch rod '71; overlie the ends of the latches and when the latches arein their rearmost positions the :hook cannot be lowered because of thelatch rod engages and rests upon the upper surfaces of the latches.However, when the latches are moved forwardly va suflicient distance thehook is allowed to drop to engage a link of the drivenchain. The latchrod 71 is retained within its bore 70 byv a pair of endcover plates 74bolted to the ends of the back-up element 69 and this arrangement isparticu-v larly advantageous since itprovides for quick removalandireplacement of the latch rod which will be subjected to constanthammering and shock'forces when the hook is droppedon the latches. Itis-notedthat the back-up element provides considerable structuralsupport-pend to withstand hard and continuous usage.

reinforces the latchrod 'to provjde an assembly adapted OperationConsidering now the operation offfthe' draw buggy above described, it isassumed that fa drawing operation has been completed and the draw buggyis being re-. turned along the bench toward the die block. At thistimethe grip bits 26 are in'their retracted .or inopera tive positionsand the hook 18 is in the raised position with the ends of the'latch rod71 resting'on the upper surfaces of'the rearwardly extended latcheswhereby thehook is free of the drive chain. The gearmotor 58 I is, ofcourse, de-energized at' this time. It is an ssumed. that metal sectionshave been loaded in the dies with the pre-pointed ends thereofprojecting past the face ofthe die block. j. I

As the draw buggyabuts against the face of the die block the electricalconnector 66 engages the connector mounted on the die block therebycompletingjan' energizing circuit for the gear motor 58. Energization ofthe gear motor causes rotation of the shouldered shaft 62 and the Wheelgears 65 carried thereby to .begin'to move I the tubular fittings 45 andthe latches '50 in a forward buggy is not in abutting relation with thedie block the gear motor is not energized and in this manner, as will Ybe further explained, the driving means is positively The hook 18 isformed yvithan integral bess'dit its l rear end and is .pivotallymounted in a rearwardly' extendingmanner for verticalpivotalmovementwithinthe recess 15,, by means of a transversely extending pivotpin ,68- s pann ing the recess". Intermediate theboss-and the downturnedprojection which is adaptedto'engage a link of the continuouslydrivenuchain, the hook increases in transverse dimension and is providedwith a transversely extending and properly formedrigid back-updirection, As the tubular fittings and latches move forward the ends ofthelatches engage the rear end of the, coil springs 55 and adrivingforce is transmitted to the drive rods'40 through these yieldable coilsprings acting" against the shoulders 53. As the ,tubularfitti ngs aremoved forward thereturn coil sprihgs-Sdfehcircling the .driver ods arecompressed and exerta force tendingto move the, tubular members andlatches to their retracted positions. g'As the drive rods move forwardthe crosshead 35 carried directly'thereby is also caused to move latches501 have not as yet moved forward 'to. such an extent that the hook isfree to drop. I loweveryasthe and, through springs 37 and plungers34,1exerts a force on the various grip bits 26 thesameinwardlyand'firrnly about the projecting pre-poi'nted-ends of.the:me'tal sec? tions. It should be apparent that the entire drivingcon: nection from the gear. in otor 58 to "the individual grip bits isyieldable'and resilient due to the inclusion" of the" various coilsprings and this allows eachofflthe' endsof the metali sections togripped. With the ends of the metal-sections thusgripped, the;

tubular and latches' continue t'o 'move forward a short distancethereby'further compressing springs be Pr perly and'i'ndependently mitretraction amazes 55 as the ends of the metal sections are now properlygripped'and this exerts a greater gripping force on the ends of themetal sections through the drive rodsthe latches move out from under thelatch rod. .The hook 18 now falls to engage a link of the driven chainso that the draw buggy is propelled along the, bench away from the dieblock. It should be understood that the latches are of such a length andare so designed with respect to theother portions of the draw buggy thatthey do not move out from under the latch rod unless and until the endportions of the metal sections are properly gripped.

When the hook falls it engages a link of the driven chain and as thechain takes up the load it rises to the elevation of the transverselyextending pivot pin 68 thereby lifting the latch rod sufiiciently abovethe latches to allow for the return movement of the latches. As soon asthe draw buggy begins, to move the gear motor 58 is de-energized as theelectrical connectors are separated from each other. The grip bits areretained in tight. gripping relation with the ends of the metal sectionssince the metal sections being pulled through the dies are underconsiderable tension.

As soon as the gear motor is de-energized and the hook is raised theelongated coil return springs 56 gain controland exert a forcesufficient to move the tubular fittings 45 and the latches S to theiroriginal positions with the latches preventing downward movement of thehook. It will be noted that the axis of thepivot pin 68 is above theplane of the, upper surfaces of the latches so that the movement ofthese members does not interfere with the drawing operation. The tubularfittings and latches will be returned to their original positions in avery fast manner under the action of the return coil springs 56 and itmay be desirable to provide means for limiting or braking the torque ofthe motor during latching of the hook. While the tubular fittings andlatches are moving to their original positions the compressive forces onthe coil springs 55 will be relieved and after sutficient travel thecoil springs 54 will act on 'the shoulders 53 to transmit a retractiveforce on the drive rods 40 thereby causing the same to move in arearward direction. The crosshead 35, which is rigidly connected to theends of the drive rods, will also move in the same direction and thismovement is sufiicient to relieve the coil springs 37 and to compressthe coil springs 38 whereby the grip bits are urged to their retractedor inoperative positions through the collars 31 and U-shapedconnectingrods 29. Of course, the tension exerted by the metal sections beingdrawn is much greater than that applied by the coil springs 38 so thatthe grip bits remain in tight gripping relation with respect to the endsof the metal sections. It is noted that the yieldable and resilientconnections provided by the various coil springs employed throughout thedraw buggy insure that the actual drawing operation will be completed ina continuous and uninterrupted manner.

To provide means to raise the hook 18 during move-, ment ,of the drawbuggy irrespective of the load and tightness of the driven chain thepair of cam members are positioned along the tracks and are adapted tobe engaged by the depending earns 72. If the hook is down when the cammembers are reached. the lower surfaces of the cams ride up the inclinedupper surfaces of the cam members thereby raising the hook sufficientlyto perof the tubular fittings, latches and drive rods. r v

v.As themetal sections leave the diesthe tension on the properly shapedand/ or formed metal sections and the grip bits will be immediatelyreleased in a sudden manner and .strike the upper surfacesof the latchesth'ereby retaining the hook in its original raised position. The drawbuggy is thus conditioned for another drawing operation with thelatches, tubular fittings, hook, drive rods and grip bits in theirretracted positions and these elements will remain in these positionsuntil the gear motor 58 is again energized. After unloading of the drawnmetal sections the draw buggy may be returned to a position adjacent thedie block for another drawing cycle.

In considering the above described operation of the draw buggy of thepresent invention it should be apparent that the same provides manyadvantages. Of particular importance is the use of the various coilsprings which not only insure proper gripping action by providingyieldable and resilient driving connections but also provide shockabsorbing means for dissipating the shock forces attendant to drawingapparatus upon the metal sections leaving the dies, etc. The gear motorand the gearing provides an excellentmeans for actuating the grippingbits wherein the ends of the metal sections are firmly and positivelygripped prior to movement of the draw buggy. The means for energizingthe driving means, although extremely simple, is advantageous since thedriving means is energized only as required while yet insuring theproper gripping of the metal sections. The hook and latchingarrangements therefor are well adapted for drawing operations and theconcept of a latching means operative in response to closure of the gripbits a short time after the ends of the metal sections are gripped isespecially important.

Gripping means In Figures 4-6 of the drawing there is shown an improvedgripping means for a draw buggy constructed in accordance with theteachings of the present invention. The draw buggy embodied in theseviews of the drawing is, with the exception of the gripping means, thesame as that described above and in order to eliminate unnecessaryrepetition in the specification like parts are designated by the samereference numerals.

' Mounted for sliding movement within each of the guide channels 25 ofthe grip bit block 24 is a grip bit holder that carries on the'forwardface thereof, by means of a dovetailed channel, a grip bit element 81having a serrated face portion 82. The grip bit holder has a verticalthrough bore 83 in the exposed rear end thereof which serves as aretaining socket for a generally cylindrical pivot block 84. A snap ring85 is used to close the bottom ofthe through bore 83 and to retain thepivot block 84 within the thus defined socket. The extreme rear endportion of the grip bit holder 80 has a vertically extending slot 86which communicates with the vertical through bore and exposes the pivotblock from the rear. In. addition to the vertical slot the rear endportion of the grip bit holder and the exposed portion of the pivotblock are formed or machined to define a frustro-conical bore 87 whoseuse will be hereinafter more fully apparent.

' Extending longitudinally with respect to the frame of the draw buggyis an actuating rod 88, the forward end portion of which is 'threadablyattached and pinned to the pivot block 84. The actuating rod extendsaxially Within the above defined frustro-conical 'bore 87 and'isslidable within a second generally cylindrical pivot block 89intermediate its'ends. The second 'pivot block 89 is received within acup-shaped holder 90 having a vertically extending slot 91 therein todefineopenings on its opposite sides- The cup-shaped holder 90 and thesecond pivot block 89 are each machined or formed to provide a pair offrus'tro-conical longitudinally extending openings 92 on oppositesidesthereof adjacent the vertically ex- .tending slot to provide clearancefor the movement of the actuating rod 88.

The rear end portion of the actuating rod 88 is threaded and mounts aretaining nut 93. Also provided in en circling relatio'n with respect tothe actuating rod 88 are a pairof compression coil springs 94 and95--the first of these springs extending from the pivot block 84 to thepivot block 89 and the second of these members being positioned betweenthe pivot block 89 and the retaining nut 93.

As is readily apparentifrom the drawing, the draw buggy comprises threepairs of grip bit holders and elements and each of these members areprovided with actuating meansincluding the pivot blocks, cup-shapedholders, actuating rods, retaining nuts, compression coil springs,etc.--as described above. In this manner of providing separate actuatingmeans for each of the grip bit holders and elements it is insured thatall of the prepointed ends of the metal sections will all be properlygripped prior to movement of the draw buggy thereby greatly facilitatingthe drawing operation.

The plurality of cup-shaped retaining members 90 are mounted in alignedfashion on a movable and transversely extending crosshead 97 which is anangle member and has a plurality of properly positioned apertures 98inthe upstanding wall thereof to permit the unobstructed passage of theplurality of actuating rods 88 therethrough. The crosshead 97 is rigidlymounted on the forward ends of the drive rods 40 and, of course, ismovable with these members.

In the operation of the gripping means the draw buggy is returned to thedie block and the gear motor 58, is energized to move the drive rodsforward in the manner heretofore described. Movement of the drive rodscauses the crosshead 97 to be carried forward-the actuating rods 88 areslidably received within the pivot blocks 89- thereby exerting a forcethrough the coil springs 94 against the pivot blocks 89. This causes thegrip bit holders 80 to slidably move'within their guide channels and thegrip bit elements forcibly and positively engage the protrudingprepointed ends of the metal sections. The position of the variousapparatus when the crosshead is in its most forward position is shown inFigure 4 of the drawing.

Probably the most important advantage of the gripping means is theelimination of a substantial amount of sliding friction. It will beobserved that in the gripping means described in connection with Figures1 and 2 of the drawing that the cooperating pairs of grip bits 25 movein a converging manner while the plungers 34 and collars 31 and 36 areguidedfor and limited to longitudinal movement and because of theseangularly related directions of guidance and movement there must berelative movement in a transverse plane between the rear ends of thegrip bits and the forward faces of'the collars 36. This relativemovement results insubstantial sliding friction in the transverse planesince these,

members are under pressure in the longitudinal direction and thisproblem is most acute at the exact moment the grip bits engage the endsof themetal sections. The sliding friction resulting from this relativemovementis considerable and may prevent the proper gripping of the endsof the metal sections thereby causing a'serious delay if one or more ofthe metal sections is notdnitially gripped or the draw is interrupted byrelease of one or more of the metal sections.

In the present gripping means, however, such sliding friction in thetransverse direction is entirely eliminated since as the grip bitelements 81Imove inwardlyi the actuating rods 88 will pivot or swing asneeded in a free and easy manner due to the pivotal connections be tweenthe grip bit holders, the cross-head and the actuating rods. Each of thepivot. blocks is freely pivotable about its vertical axis and the.frustro-conical bores are of .s'uch size and shap'eto'permit swingingmovement of the interference between adjacent actuating rods. Inessence, the gripping means is characterized by its complete lack ofsliding friction in. the transverse direction and proper and positivegripping of the ends of the metal section is always insured.

A short time after the ends of the metal sections are properly grippedthe hookof the draw buggy is dropped to engage a link of the drivenchain and'the draw buggy moves away from the die block therebyde-energizing the gear motor 58. The previously compressed return coilsprings 56 gain control and drive the drive rods 40 and the crosshead 97to the rear thereby relieving the coil springs 94 and compressing thecoil springs 95 which exert forces tending to retract the grip bitelements to their inoperative positions. The metal sections are underconsiderable tension during drawing and this precludes retraction of thegrip belt elements during drawing opits simplicity of construction butyet is operable in an improved manner. One important aspect thereof isthe extreme case with which the gripping means may be removed andreplaced. The pivot blocks 84 and 89, springs 94 and 95, retaining nut93 and actuating rod 88 form a self-contained assembly for each of thegrip bit elements which may be lifted directly from the draw buggy dueto the provision of the various vertically extending slots 86, 91 and 98in the grip bit holders, cup-shaped holders and crosshead, respectively.i

Although I have accomplished the objects initially set forth, it shouldbe apparent that many changes may be made in the illustrated embodimentsof the invention without departing from the teaching thereof.Accordingly reference should be had to the following appended claims indetermining the true scope and intent of the invention.

I claim:

1. In a drawcarriage for metal drawing equipment hav-v ing an elongatedframe and at least one pair of converging grip bits carried by one endof said frame and guided for movement in converging directions wherebythe bits may be moved into and out of engagement with a work piece theimprovement comprising a pair of transversely pinion gears keyed thereonand meshing with said rack gears, an electric motor mounted on saidframe between.

, saidrods, reduction gearing between the 'output sh'aftof 2 the motorandsaid transverse shaft, and a-plug-in type of y electrical connectionrigidly carried by said frame adjacent said grip bits and adapted toengage a connection on said carriage whereby current is supplied tothe'motor when said carriage isat the die block of said equipment.

2. Apparatus according to claim 1 further including energy storage meansto automatically move said rods and rack and pinion gears and reductiongearing back to their initial starting positions upon de-energization ofsaid motor when said carriage moves away from said die block. 1 '3.Apparatus according to claim 1 wherein a pivoted draw-chain hook and alatchto holdthe sameYintupper chain-free position is located'on theopposite end of said frame from said grip bits the further improvementof I providing a longitudinally elongated latch and actuating. Q linkagebetween said latch'and said rack gears whereby.

fs'aid latch is released onlyupon said rods'being advanced apredetermined distance in grip-bit closing direction by 1,574,381.Entenmann Feb. 23, 1926 said motor. 1,951,073 Wallis Mar. 13, 19342,404,234 Kerr July 16, 1946 References Cited in the file of this patent2 535 9 1 Schiller Aug. 10, 5 UNITED STATES PATENTS 5 2,845,171 HeymJuly 29, 1958 672,914 Quimby Apr. 30, 1901 FOREIGN PATENTS 715,862Qulmby 16, 1902 451,481 Great Britain Aug. 6, 1935 868,375 TWer 15, 1907595,470 1 Great Britain Dec. 5, 1947

